For purposes of the disclosure and claims, the term "filaments" applies to monofilaments and to plied or unplied combinations of two or more monofilaments or fibrous strands twisted into threads, yarns and/or cables or as untwisted bundles, tows, etc. The filaments and/or fibers are made of synthetic, spinnable, thermoplastic polymers.
Devices for laying such filaments, upon their delivery from spinning installations in the case of freshly spun, stretched or unstretched filaments, include rotating delivery tubes or piddlers which deliver the filaments as helices to canisters or other collectors. U.S. Pat. Nos. 2,971,683 and 3,706,407 describe devices of this type. The rotating guide tube of these devices has a simple curvature and in its emergence zone--as seen in projection onto its plane of rotation--is radially directed. The disadvantage of this tube construction lies in that the velocity of the filament(s) at the exit of the guide tube, with respect to a spatially fixed coordinate system extending through the axis of rotation of the tube, is further increased with respect to the velocity of filament feed to the guide tube, whereby the filament(s) gain kinetic energy, instead of reducing this energy. This is clear if one realizes that, to the radially directed velocity of the filament(s) passing out the exit end of the tube, there must be added vectorially the peripheral velocity of the rotating guide tube at the emergence end. Therefore, the resulting velocity of the exiting filament(s) is always greater than the feed volocity. The consequence of the velocity increase is that the filament(s), after leaving the rotating guide tube, is/are borne so far radially outwardly that the air resistance between the exiting filament(s) and the substantially stationary ambient air and the tension force caused by the rotary movement of the downstream filament helices suffice to deflect the filament(s) at the emergence from the guide tube oppositely to the orbiting direction of the guide tube's discharge opening. This can lead, especially in the case of high linear velocity of the filament(s), to the result that the lay-down of the filament(s) in the receptacle is not satisfactory. On the one hand, helices of the filament(s) can easily expand beyond the edge of the receptacle. On the other hand, the rotary movement of the free helices in the zone between guide tube and receptacle tend to entangle with the already deposited spiral windings of the filaments. The entanglements severely impair the later removal of the filament(s). The rotary movement of the helices about the axis of rotation is necessary in order to generate by centrifugal forces the necessary pulling force for the deflection of the filament(s) at the exit of the radially direction tube.
To explain the rotary movement occurring in a device of the category mentioned: Upon the vertical falling movement of an observed filament there is superimposed a rotary movement. The resulting curve path of the filament(s) is a helical line. This is to be distinguished from the filament helix visible to the observer in a stop-action photograph, which is interpreted as a flow path which starts at the exit of the guide tube and rotates with the tube about the axis of rotation of the device, and through which each filament travels.
German Pat. No. 1,115,622 and German Published application AS No. 1,510,310 describe known rotary heads having guide tubes for the filament(s) to be deposited exiting tangentially to their rotary arcs. These structures have an inherently high tendency to clog because, in the zone of the emergence opening of a tangentially directed guide tube, the resultant acceleration imparted to the exiting filaments is directed perpendicularly to the filament passage. The resultant high friction forces in the conveyance direction lead to the clogging tendencies. Such a rotary head, therefore, can function effectively only because the head lays the exiting filament(s) onto the layers already deposited in the collecting canister (cf. for example, German Pat. No. 1,019,222), whereby a pull is exerted on the filament(s) emerging from the guide passage of the rotating head. These known devices are used for the depositing of spun or drawn bundles in the fiber yarn spinning preparation machines at substantially lower operating speeds.